Recent human and animal nutrition research studies concerning possible associations between zinc (Zn) and vitamin A are reviewed and critiqued. A consistent finding was the depression of blood vitamin A levels in Zn-deficient animals having adequate vitamin A in their diets. This depression appears to be due to a nonspecific response to food intake and growth restrictions associated with Zn deficiency, rather than to Zn deficiency per se. Liver vitamin A levels are usually unaltered in Zn deficiency, suggesting that vitamin A absorption and transport to the liver are unimpaired. Zn deficiency, however, affects both the plasma and liver retinol-binding protein (RBP) levels; hence, Zn deficiency may impair RBP synthesis. Limited human studies suggest that Zn supplementation may benefit vitamin A metabolism only in the case of Zn deficiency. (wz)